Question

In CuSO\(_4\cdot 5H_2O\), the number of coordinated and hydrogen bonded water molecules present are respectively:

• A. 5, 0
• B. 4, 1
• C. 3, 2
• D. 1, 4

Hint:

In metal hydrates, coordinated water molecules are directly bonded to the metal ion, while lattice water is hydrogen bonded.

Answer 1

The Correct Option is B

Step 1: Recognizing the compound.
CuSO₄·5H₂O is copper(II) sulfate pentahydrate, incorporating five water molecules per formula unit.

Step 2: Coordination arrangement.
Four of the five water molecules directly coordinate to the Cu²⁺ ion, forming the [Cu(H₂O)₄]²⁺ complex.

Step 3: Hydrogen-bonded water.
The remaining one water molecule is not bound to the metal center; instead, it resides as lattice water held by hydrogen bonding within the crystal lattice.

Step 4: Conclusion.
Hence, the numbers of coordinated and hydrogen-bonded water molecules are 4 and 1, respectively.